GPS spike - question

NEWTON <[email hidden]> wrote

Quoted message said:

I use a Garmin Summit combined with Memory Map
version 2004.

For some while now my Summit has started linking the last
walk and the current walk with a straight-as-an-arrow line
on my map page. I was hoping the problem would go away when
I upgraded MM to the 2004 version but it didn't. The unit
seems to remember where it was when I turned it off and
then finds where I am as I switch it on and links the two
locations together no matter where in the UK the two
locations are. This is very annoying!

It's a simple matter to get rid of the track line, I just
delete a couple of track points at the extremity of the
previous walk and the line disappears - but when I use
'show all' it returns.

Any ideas how to sort this?

It happens with my Summit, and my Vista.

When the unit 'wakes up' at a new location, it sometimes
plants a few track points back at the place where it was
last switched off!

I use OziExplorer, and when I display the track list it is
easy to delete the spurious track points, so it doesn't
really bother me.

You could try stopping the track log every time you finished
a trip, then switching it on once 'lock' has been achieved
at the beginning of your next walk, but is it worth the
trouble? :-)

I just tried that on the Summit, but couldn't remember how
to switch off the track log!
--
Gordon

Gordon said:

When the unit 'wakes up' at a new location, it sometimes
plants a few track points back at the place where it was
last switched off!

I use OziExplorer, and when I display the track list it is
easy to delete the spurious track points, so it doesn't
really bother me.

You could try stopping the track log every time you
finished a trip, then switching it on once 'lock' has been
achieved at the beginning of your next walk, but is it
worth the trouble? :-)

Yes. I always switch track recording off at the end of a
walk, mainly as a precaution in case it accidentally gets
switched on again. It did this a couple of times and
recorded the drive home, wiping out part of the walk.

The advantage of turning it on at the start of a walk is
that I can wait until I get a good lock before I start
recording. This avoids recording the spurious points that
usually occur when you first switch it on and it tries to
figure out where it is.

The disadvantage is that you can forget to turn track
recording on, so I always make a point of looking at the map
screen as I start walking to check that the track is being
recorded. It's become a habit now so I never forget. Once
the new pathways are permanently burnt into your brain it's
not a problem, but you do have to make the effort to
remember each time until it becomes habitual.

Paul
--
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wildwales.fsnet.co.ukwildwales.fsnet.co.ukOpen ↗
photosig.comuserphotosOpen ↗

NEWTON said:

I use a Garmin Summit combined with Memory Map
version 2004.

For some while now my Summit has started linking the last
walk and the current walk with a straight-as-an-arrow line
on my map page. I was hoping the problem would go away when
I upgraded MM to the 2004 version but it didn't. The unit
seems to remember where it was when I turned it off and
then finds where I am as I switch it on and links the two
locations together no matter where in the UK the two
locations are. This is very annoying!

It's a simple matter to get rid of the track line, I just
delete a couple of track points at the extremity of the
previous walk and the line disappears - but when I use
'show all' it returns.

Any ideas how to sort this?

It seems to be a 'feature' of the MM software. If I plot the
same track in OZI these long straight lines aren't drawn. I
guess OZI is just more intelligent. I will ask the author
how he does it !

The problem is worse for me because, using OZI, I have
joined up a number of tracks to make a longer one, as part
of my map-creation process. Some of the tracks go opposite
ways, as well. OZI plots all of this quite tidily, but MM
produces a complete haze of these arrow-tracks, trying to
join up the beginnings & ends. Hopeless !

I notice you used the word 'spike in the header. As a signed-
up pedant, I would like the word 'spike' kept for the
'spikes' which appear on a track plotting (even on OZI)
after a momentary loss of lock. They look very like real
spikes, whereas the features you describe look like 'arrow-
tracks' as you say - may I suggest that term is used ?

So a long line plotted to incorrectly join two widely
spaced trackpoints is now officially christened a NEWTON
ARROW-TRACK !!

Two lines drawn to and from a wild trackpoint are to be
called a SPIKE.

Jim Hutton

Jim Hutton said:

It seems to be a 'feature' of the MM software. If I plot
the same track in OZI these long straight lines aren't
drawn. I guess OZI is just more intelligent. I will ask
the author how he does it !

Anquet does the same. Just goes to show that these are not
dedicated GPS programs. When you turn a GPS off and back on
it starts a new track segment (one reason why I don't like
to switch it off even when I stop for a break).

If you take a look at an Ozi track file in a text editor
you'll see that these start points are clearly indicated.
After the lat/long there is a or a 1. 1 indicates a new
track segment, 0 indicates a continuation of the track. It
shouldn't be difficult to recognise this in Anquet or
MM.

Quoted message said:

I notice you used the word 'spike in the header. As a signed-
up pedant, I would like the word 'spike' kept for the
'spikes' which appear on a track plotting (even on OZI)
after a momentary loss of lock.

Agreed.

Paul
--
wilderness-wales.co.ukwilderness-wales.co.ukOpen ↗
wildwales.fsnet.co.ukwildwales.fsnet.co.ukOpen ↗
photosig.comuserphotosOpen ↗

Quoted message said:

I notice you used the word 'spike in the header. As a signed-
up pedant, I would like the word 'spike' kept for the
'spikes' which appear on a track plotting (even on OZI)
after a momentary loss of lock. They look very like real
spikes, whereas the features you describe look like 'arrow-
tracks' as you say - may I suggest that term is used ?

Yep, okay. I used the word 'spike' in a moment of utter
madness forgetting that there are other spikes assossiated
with the tracks.

Quoted message said:

So a long line plotted to incorrectly join two widely
spaced trackpoints is now officially christened a NEWTON
ARROW-TRACK !!

I'm highly honoured :-)

Quoted message said:

Two lines drawn to and from a wild trackpoint are to be
called a SPIKE.

Seems good to me.

Dave

Gordon said:

NEWTON <[email hidden]> wrote

Quoted message said:

I use a Garmin Summit combined with Memory Map
version 2004.

Quoted message said:

Quoted message said:

For some while now my Summit has started linking the last
walk and the current walk with a straight-as-an-arrow line
on my map page. I was hoping the problem would go away
when I upgraded MM to the 2004 version but it didn't. The
unit seems to remember where it was when I turned it off
and then finds where I am as I switch it on and links the
two locations together no matter where in the UK the two
locations are. This is very annoying!

It's a simple matter to get rid of the track line, I just
delete a couple of track points at the extremity of the
previous walk and the line disappears - but when I use
'show all' it returns.

Any ideas how to sort this?

Quoted message said:

It happens with my Summit, and my Vista.

Quoted message said:

When the unit 'wakes up' at a new location, it sometimes
plants a few track points back at the place where it was
last switched off!

The altimeter units will drop trackpoints even without GPS
signals, if they detect a significant in altitude. Without
GPS lock, they simply default the position of the trackpoint
to the last locked location. It's likely to do this if you
switch on and give it a hard time, so that it takes a while
to lock, such as throwing it on the dash and driving off.
It's less likely if you're kind to it, e.g., switch on when
stationary with good skyview.

Quoted message said:

You could try stopping the track log every time you
finished a trip, then switching it on once 'lock' has been
achieved at the beginning of your next walk, but is it
worth the trouble? :-)

Quoted message said:

I just tried that on the Summit, but couldn't remember how
to switch off the track log!

I don't think you can switch track logging off on the
Summit.

--
Chris Malcolm [email hidden] +44 (0)131 651 3445 DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
["]http://www.dai.ed.ac.uk/homes/cam/]

Quoted message said:

Quoted message said:

When the unit 'wakes up' at a new location, it sometimes
plants a few track points back at the place where it was
last switched off!

The altimeter units will drop trackpoints even without GPS
signals, if they detect a significant in altitude. Without
GPS lock, they simply default the position of the
trackpoint to the last locked location. It's likely to do
this if you switch on and give it a hard time, so that it
takes a while to lock, such as throwing it on the dash and
driving off. It's less likely if you're kind to it, e.g.,
switch on when stationary with good skyview.

I'm always kind to my Summit!

What I generally do is switch the unit on and put it on the
roof of the car whilst I boot up and get ready. It has
usually achieved lock by the time I'm ready to walk.

Just rewinding a bit, when I asked this question I think the
consensus was that the Summit and Memory Map combined will
always have exhibited this 'characteristic'. I don't
remember that. I know I didn't get the 'Newton Arrow' as Jim
christened it whilst using Ozi but I thought it only
appeared on MM after I had been using it a while. Memory
fades though and I might be incorrect.

--
Dave Newton

Lake District walk&image site daves-lakeland-daves-lakeland-Open ↗
mountains.co.uk

Chris Malcolm <[email hidden]> wrote

(Gordon)

Quoted message said:

Quoted message said:

I just tried that on the Summit, but couldn't remember how
to switch off the track log!

I don't think you can switch track logging off on the
Summit.

I suppose you could switch the GPS function off, but that
wouldn't help, because you would have the same problem when
you switched on. I am chasing my own tail now..... ;-)
--
Gordon

NEWTON <[email hidden]> wrote

Quoted message said:

I'm always kind to my Summit!

What I generally do is switch the unit on and put it on the
roof of the car whilst I boot up and get ready. It has
usually achieved lock by the time I'm ready to walk.

That's what I do. Thus far I haven't left it there and
walked away.....

Quoted message said:

Just rewinding a bit, when I asked this question I think
the consensus was that the Summit and Memory Map combined
will always have exhibited this 'characteristic'. I don't
remember that. I know I didn't get the 'Newton Arrow' as
Jim christened it whilst using Ozi but I thought it only
appeared on MM after I had been using it a while. Memory
fades though and I might be incorrect.

It happens when I download tracks into Ozi, at least it does
when they are multiple tracks from separate walks.
--
Gordon

I find that if I clear the trip log and the track before I
start walking it prevents me getting the Newton track line
from the previous walk. However, don't you think that Garmin
ought to give you a choice of whether you want the GPs to
fill in the gap or not?

--
Martin Richardson
227/284 Munros - 20% to go 34/34 'Furths' & 439/439 Nuttalls
- 0% to go
228/89 Donalds - 53% to go 0/? Himalayans - 100% to go
229/1552 Marilyns - 73% to go

Martin Richardson <[email hidden]> wrote

Quoted message said:

I find that if I clear the trip log and the track before I
start walking it prevents me getting the Newton track line
from the previous walk. However, don't you think that
Garmin ought to give you a choice of whether you want the
GPs to fill in the gap or not?

Normally I do that - being a 'day walker' rather than an
expedition walker. :-)

However, I started totting up the total walking for each
week, and on the Vista you can reset the TRIP without
resetting the ODOMETER, just like on a moty car. In fact you
can select which of a number of items you wish to reset.

So the odometer can be used to total my week's walking, and
the trip reset each day, but I still prefer to download each
day's walk into a file called Weekxx_Monday, etc, then tidy
each up before concatenating them into a Weekxx_Final file.

From this you can deduce what an exciting life I lead.....

But today I connected up my mate's new XP machine and
commissioned it for him. I was favourably impressed, for
£599 he got a decent PC.
--
Gordon

Martin Richardson said:

I find that if I clear the trip log and the track before I
start walking it prevents me getting the Newton track line
from the previous walk. However, don't you think that
Garmin ought to give you a choice of whether you want the
GPs to fill in the gap or not?

It's not the Garmin GPS which fills the gaps, it's the PC
software you use to display the tracks. Every track break is
clearly marked in the Garmin output. Some software honours
those marked breaks, some fills them in, some fills in those
which are close in time and leaves those with longer time
breaks, etc.. If you use a different program you may get
different track breaks displayed or options to control them.

--
Chris Malcolm [email hidden] +44 (0)131 651 3445 DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
["]http://www.dai.ed.ac.uk/homes/cam/]

In message <[email hidden]>, Gordon
<[email hidden]> writes

Quoted message said:

Martin Richardson <[email hidden]> wrote

Quoted message said:

I find that if I clear the trip log and the track before I
start walking it prevents me getting the Newton track line
from the previous walk. However, don't you think that
Garmin ought to give you a choice of whether you want the
GPs to fill in the gap or not?

Normally I do that - being a 'day walker' rather than an
expedition walker. :-)

However, I started totting up the total walking for
each week, and on the Vista you can reset the TRIP
without resetting the ODOMETER, just like on a moty
car. In fact you can select which of a number of items
you wish to reset.

So the odometer can be used to total my week's walking,
and the trip reset each day, but I still prefer to
download each day's walk into a file called Weekxx_Monday,
etc, then tidy each up before concatenating them into a
Weekxx_Final file.

From this you can deduce what an exciting life I lead.....

But today I connected up my mate's new XP machine and
commissioned it for him. I was favourably impressed, for
£599 he got a decent PC.

Bowlers on a weekend - for £599 you should get a very high
spec. I'd expect DVD writers and the full works.

--
Martin Richardson
227/284 Munros - 20% to go 34/34 'Furths' & 439/439 Nuttalls
- 0% to go
228/89 Donalds - 53% to go 0/? Himalayans - 100% to go
229/1552 Marilyns - 73% to go

Paul Saunders <[email hidden]> wrote

Quoted message said:

Gordon said:

on the Vista you can reset the TRIP without resetting the
ODOMETER,

Quoted message said:

So the odometer can be used to total my week's walking,
and the trip reset each day,

Pity you can't "pause" the odometer (and trip counter for
that matter). Occasionally I use the GPS in the car to help
locate key road junctions in unfamiliar areas, but although
I can disable track recording, the trip counter still
clocks up, thus screwing up any attempt at an accumulated
walking distance.

So I just zero it at the start of each walk and write the
results down.

I use the Summit for navigating in the car, by plotting a
track of the route in OziExplorer and uploading it.

The Summit has a thick track, easy to see at a glance in the
car, whereas the definition is much finer in the Vista, and
not so easy in a moving vehicle.
--
Gordon

Gordon said:

on the Vista you can reset the TRIP without resetting the
ODOMETER,

Quoted message said:

So the odometer can be used to total my week's walking,
and the trip reset each day,

Pity you can't "pause" the odometer (and trip counter for
that matter). Occasionally I use the GPS in the car to help
locate key road junctions in unfamiliar areas, but although
I can disable track recording, the trip counter still
clocks up, thus screwing up any attempt at an accumulated
walking distance.

So I just zero it at the start of each walk and write the
results down.

Paul
--
wilderness-wales.co.ukwilderness-wales.co.ukOpen ↗
wildwales.fsnet.co.ukwildwales.fsnet.co.ukOpen ↗
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